This invention relates to active networks and more particularly to networks having biquadratic transfer functions.
A biquad circuit is considered to be one having a biquadratic transfer function which is generally defined as one where the denominator includes a second-order or s.sup.2 term and the numerator is of degree two or less. Biquad circuits employing three and four operational amplifiers to simulate circuits having prescribed biquadratic transfer functions are described in prior-art literature such as "A Step-by-Step Active-Filter Design" by J. Tow, IEEE Spectrum, December 1969, pp. 64 - 68; and the Biquad -- Parts I and II, by Lee C. Thomas, IEEE Transactions on Circuit Theory, volume Ct 18-3, May 1971, pp. 350-361.
An object of this invention is the provision of a versatile network having only three active elements and which can be adjusted to have prescribed second-order transfer functions.